21641123851 has 4 divisors (see below), whose sum is σ = 21784442704. Its totient is φ = 21497805000.

The previous prime is 21641123837. The next prime is 21641123857. The reversal of 21641123851 is 15832114612.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21641123851 - 2³¹ = 19493640203 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21641123857) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 71659200 + ... + 71659501.

It is an arithmetic number, because the mean of its divisors is an integer number (5446110676).

Almost surely, 2^21641123851 is an apocalyptic number.

21641123851 is a deficient number, since it is larger than the sum of its proper divisors (143318853).

21641123851 is a wasteful number, since it uses less digits than its factorization.

21641123851 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 143318852.

The product of its digits is 11520, while the sum is 34.

The spelling of 21641123851 in words is "twenty-one billion, six hundred forty-one million, one hundred twenty-three thousand, eight hundred fifty-one".